Make A Left At Mars And Head Straight For Uranus — You Can’t Miss It!

The scene this evening at dusk with the lunar crescent, Mars and Uranus. Stellarium

I have a friend I know I’ll be hearing from once he reads that title. For him and others who enjoy poking fun at the solar system’s seventh planet, here’s a selection of Uranus jokes. Now for some great news. If you’d like to see Uranus this week, Mars will get you there. The Red Planet is approaching the “other blue planet” and will skim less than 1° north of it when the two are in conjunction on Tuesday, Feb. 12.

The circle is a little more than 5° across — about the field of view in a pair of binoculars. Mars slides between the stars Omicron (left) and Pi Piscium as it moves toward and then past Uranus over the coming 7 nights. This view shows the orientation of the sky the way you see it facing southwest toward Mars. Stellarium with additions by the author

But don’t wait that long. Tonight, they’ll be just shy of 3° apart and easily fit in the field of view of any pair of binoculars. Then over the next few nights you can watch Mars approach the more distant planet until conjunction and beyond if you like. Mars shines at 1st magnitude and can’t be missed. It’s the only bright “star” shining high in the western sky at dusk. And you can’t mistake its orange color. The moon glides 6° south of the planet (equal to three fingers held together at arm’s length against the sky) on Sunday, Feb. 10.

Uranus, Earth and moon compared. Uranus has an atmosphere of hydrogen and helium with clouds of ammonia and methane. Methane absorbs red light and reflects blue, giving the planet its characteristic color. The white dot over Uranus is the moon Ariel casting a shadow on the cloud deck below. NASA / ESA/ L. Sromovsky

Uranus glows at magnitude 5.8, right around the naked-eye limit from the countryside. The moon is thickening though and relatively nearby, so you’ll definitely need binoculars. Just point them at the Red Planet and use the map to locate Uranus. Because of its great distance, Uranus looks exactly like a star in binoculars. A small telescope magnifying around 100x will show it as a tiny disk. The blue planet, colored so by methane in its atmosphere, lies 1.9 billion miles (3 billion km) from the Earth this week or nearly 13 times farther than Mars.

Like Mars, Uranus is also moving along its orbit but so much more slowly that it’s almost stationary in the sky compared to speedy Mars. Even in large telescopes the planet doesn’t much different from a featureless blue cue ball. But not always. Belts and storms have been recorded there, and since 1990, the Hubble Space Telescope has kept a yearly watch on both Uranus and the other ice-giant planet, Neptune. Astronomers monitor the weather and long-term seasonal changes at these distant worlds.

Only after 84 years would a hypothetical Uranian citizen be able to celebrate their 1st birthday — that’s how long it takes the planet to make one orbit of the sun. Uranus rotates on its side with each of its four seasons lasting 21 years. Nature of the Universe with additions by the author

Photos taken last fall have revealed a vast, bright cap of clouds over Uranus’s polar regions which may form due to changes in atmospheric flows brought on by the changing seasons. The cap is much more prominent compared to its appearance in 1986 during the Voyager 2 flyby. Hard to believe, but even at that distance there are seasons.

Recall that the planet’s axis is tilted 98°, so it’s basically spinning on its side.The north pole faces the sun for a quarter of its orbit (21 years); half an orbit later, it’s plunged into darkness for 21 years. Right now, Uranus is coming up on the middle of its summer season when the sun shines almost directly down on the north pole and never sets. When Voyager 2 snapped closeups 33 years ago, it was only just emerging from a long, dark winter. No wonder we’re seeing cloud changes.

This Hubble Space Telescope photo of Uranus, taken in Nov. 2018, reveals a vast bright stormy cloud cap across the planet’s north pole, a bright methane-ice cloud and a narrow band near he equator. NASAESA, and A. Simon (NASA / GSFC), and M. Wong and A. Hsu (Univ. of California)

The Hubble photo also shows a large, compact methane-ice cloud along the edge of the polar cap, a feature bright enough to show in photos taken by amateur astronomers, and a narrow cloud belt north of the equator. Scientists are still mystified how such narrow bands form on a planet with broad, westward-blowing wind jets. Uranus has no solid surface. Its atmosphere of hydrogen and helium surrounds a slushy-icy, water-rich interior with a possible rocky core at the center of it all.

So go ahead and get those binoculars pointed for a look at this marvel. Look more than once, and you’ll see how quickly Mars moves across the sky.

7 Responses

  1. Troy

    Pretty cool. I was thinking, something that conspicuous would be something Damien Peach could have imaged, and sure enough he did.

    1. astrobob

      Let me know if you see it, Jason. It shouldn’t be too hard. Now is the best time with the moon still a crescent.

  2. kevan hubbard

    Thanks for the map! I got Uranus tonight with my 8×25 opticron monocular.the nearby stars do add a little bit on confusion but it’s easy enough.due to the moon coming into phase I doubt that there will be anyone seeing the conjunction naked eye(well they’re going to see mars but not Uranus!).you need a dark Moon free sky to see the dimest naked eye planet with no optical aid.

      1. kevan hubbard

        Spotted it again tonight again through the 8×25 monocular.it forms a triangle,on the 10th February at least,with omicron Pisces and Mars and there’s a faint star above(east)of Uranus possibly eta Pisces?your map just shows this one as ‘star’but eta looks in the right place whatever it is it’s about the same magnitude as Uranus whilst omicron must be about 4.5 magnitude.

        1. astrobob

          Kevan, Eta Psc is out of the field in my diagram. Its magnitude is 3.8 and well to the right of Mars. The “star” marked has no Greek letter. It’s mag. 5.9 and has a rather long name, the reason I left is simply as “star.”

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